Sub-Barrier Fusion Coupled-Channels Calculations for ¹⁶O + ^16,18O

A simple version of coupled channels approach is generalized to the light system ¹⁶O + ^16,18O for subbarrier fusion study. It shows that the contribution of the inelastic channel of 2⁺₁ state in ¹⁸O is small, while neutron-pair transfer reaction channel of vanishing Q-value is required to explain the trend of the existing low-energy fusion data.